With rapid development of high-tech industries, various electronic devices such as computer or servers become essential in our lives. As known, the heat-dissipating efficacy of the electronic device influences the operating stability and the use life of the overall system. For increasing the heat-dissipating efficacy of the electronic device, a cooling device is usually installed within the electronic device or the ambient environment to cool the electronic device.
As known, an air-cooled heat exchanger is one of the common coolers for guiding the ambient air to cool the electronic components within the electronic device. Generally, the air-cooled heat exchanger has a first fan and a second fan. The first fan performs an internal circulation. By the internal circulation, the indoor hot airflow generated from the electronic device is inhaled into the air-cooled heat exchanger through an upper position of the air-cooled heat exchanger. The second fan performs an external circulation. By the external circulation, the ambient cool airflow is introduced into the air-cooled heat exchanger through a lower position of the air-cooled heat exchanger. Through plural heat-dissipating fins within the air-cooled heat exchanger, the heat of the indoor hot airflow is transferred to the ambient cool air. In such way, the temperature of the electronic device is reduced.
The second fan of the air-cooled heat exchanger is an axial-flow fan or a centrifugal fan. Generally, the axial-flow fan may result in a relatively higher capacity of airflow. In addition, the airflow-entering direction and the airflow-leaving direction of the axial-flow fan are identical. As such, the heated ambient cool airflow can be effectively exhausted to the surroundings. The axial-flow fan, however, generates undesired noise. In addition, in a case that the air-cooled heat exchanger with the axial-flow fan is operated in a high air-resistance occasion or an obstructing object is placed at the airflow outlet side of the axial-flow fan, the air pressure acting on the airflow outlet side of the axial-flow fan is obviously attenuated. Under this circumstance, the airflow capacity is largely reduced, and thus the heat-dissipating efficacy of the air-cooled heat exchanger is impaired.
Although the centrifugal fan has low noise and large air pressure, there are still some drawbacks. For example, since the angle between the airflow-entering direction and the airflow-leaving direction of the centrifugal fan is substantially 90 degrees, the air-cooled heat exchanger is usually equipped with an additional hood at the airflow outlet side. As such, the heated ambient cool airflow within the air-cooled heat exchanger is introduced into the airflow inlet of the centrifugal fan, then turned by 90 degrees, and finally exhausted to the surroundings through the hood. However, the use of the additional hood increases the fabricating cost of the air-cooled heat exchanger.
Therefore, there is a need of providing an integrated fan with the benefits of an axial-flow fan and a centrifugal fan to obviate the drawbacks encountered from the prior art.